Hair treatment



Patented Dec. 4, 1945 UNITED STATES PATENT OFFICE HAIR TREATMENT Jose B. Calva, St. Paul, Minn.

No Drawing. Application February 28, 1941,

Serial No. 381,135

11 Claims.

This invention relates to the treatment of the hair of living beings, either to straighten the hair, in the event it is naturally curly or kinky, or to impart curl thereto in the event it is naturally straight. To accomplish this result, there is produced a chemical modification of the basic material of which the hair is composed, together with the formation in situ of modifying resinous substances andin some instances also with the formation of waxlike substances.

Hair is composed of keratinous material of very complex molecular constitution. While the structure of the keratinous molecule in hair' has never been positively determined, it is known to include amino groups and inner salt linkages. To account for the chemical reactions of keratin, Astbury and Speakman suggest the chemical Structure I given below, wherein the amino groups are present in the lysine and argenine nuclei.

I have discovered that by the use of suitable activating and reacting agents under controlled conditions, far reaching, relatively permanent physical changes can be produced in the hair, and as a result naturally curly or kinky hair of living beings can be straightened as desired and conversely naturally straight hair can be rendered curly. The changes thus produced are relatively permanent, even in the presence of moisture.

In the natural state, water readily affects the keratin'ous molecules, producing a softening and relaxation of the hair, with the result that the hair assumes certain well-established physical conditions. Thus, Negro hair, which has a natural tendency to assume a spiral configuration, does so readily when wet and likewise the hair of most white people naturally tends to straighten.

Negro hair can be temporarily straightened by known processes of pressing, i. e. combing with heat, but the thus temporarily straightened hair quickly resumes its spiral, kinky configuration when wetted since the keratinous material has remained unchanged. Likewise, the hair of white people can be curled with a hot iron but the curl likewise disappears when the hair is wetted.

According to the present invention, far-reach ing changes are caused to take place in the keratinous material itself, together with resinification and in some instances wax formation in situ, whereby the hair is rendered relatively waterproof and the hair when then "straightened or curled as the case may be, remains so even designate as a reacting agent.

though the hair is exposed to moisture or is wetted. By the term "in situ is meant the formation of the resin in and on the hair by application of the resin forming reagents thereto as distinguished from the separate making of a resinoid substance and dissolving it by suitable means and then applying it to the fibres, and then subsequently eliminating or removing the solvent by physical or chemical means; as for example, by dissolving a material'or synthetic resin in a solvent which is later eliminated by evaporation, or by dissolving this resin or resinoid substance which reacts with that chemical whose reaction product is later broken up by use of a third re-agent such for example as rosin soap, precipitated subsequently with an acid producing substance. Of course, as the hair grows, the untreated new growth has its natural configuration.

It is an object of this invention to provide improved methods of treating the hair of living beings to produce relatively permanent chemical and physical changes, for either straightening curly 0r kinky hair or curling straight hair.

In carrying out the invention, the hair is reacted with an agent which I herein designate as an activating agent under controlled pH con-' ditions, the hair being so activated is subjected to the action of another material which I herein When so processed, and the hair is straightened or curled with heat as desired, the resulting effect is relatively permanent and resists change and reversion to its original condition even in the presence of moisture.

The activating agent" for the processing of the hair may have a pH in the range of 1 to 10, but preferably in the ranges of about 1 to 4.8 and 5.2 to 10 which are the ranges covering either (1) Potassium chloride and hydrochloric acid bufiered to pH 1-2 (2) Potassium acid phthalate and hydrochloric acid in proportions to produce pH 2.2-3.8

(3) Potassium acid phthalate and caustic soda. in proportions to produce pH 4-4.8

Mono potassium orthophosphate and caustic soda in proportion to produce pH 5.2-8.0

Caustic soda and boric acid for the range pH 7.8 to 10 Alpha-naphthaline sulfonic acid 1,5-naphthaline disulfonic acid I-hydroxy-S-naphthalene sulfonic acid 2-hydroxy-l-naphthalene sulfonic acid Benzene-sulfonic acid Tolyl-sulfonic acid Phenol-sulfonic acid Resorcinol sulfonic acid Salicylic-sulfonic acid Resorcinol disulfonic acid Isopropyl-naphthalene sulfonic acid Cresol sulfonic acid Acetic acid Lactic acid Triethanolamine (21) Morpholine (22) Aluminum sulfate As "activating agents," there may also be used the water-soluble aluminum, ammonium, magnesium, potassium, barium, calcium, sodium, pyridinium or amine salts such as triethanolammonium salts, etc., of the acids listed above, or mixtures of such salts or mixtures of two or more acids and salts.

Some of the above-mentioned materials inherently establish the hydrogen ion concentrations in the specified ranges of pH 1-10, preferably in the ranges 1-4.8 and 5.2 to 10. others require additional pH controlling ingredients to act as buffers to establish and maintain the prescribed pI-I condition.

The activating agent of the present invention may be described as an ionizable substance acting within the pH range aforementioned and capable of arousing the desired reactivity conditions in the hair to which it is applied. In many of the above-mentioned ionizable substances which I have specified as exemplary of the "activating agents for use in the present invention, one of the ions of the activating agent" is in itself capable of resiniflcation with aldehydes, and for best results, I therefore prefer to use as the activating agent compounds having the such secondary function of resiniflcation as will be explained in greater detail below. Where the term activating agent is used herein, it is intended to mean a substance or mixture of substances having the prescribed pH. and preferably, though not necessarily, of the type capable of releasing ions capable of resinification with aldehydes, particularly formaldehyde or its polymerS as well as formaldehyde yielding substances.

As reacting agents" I use any compound having a reactive aldehyde function when applied in a suitable solvent or vehicle; and capable of forming condensation products with the keratin of the hair, as an example there may be mentioned a simple water-solution of formaldehyde of 3% to 40% strength. Substances such as paraformaldehyde, hexamethylenetetramine or sodium bisulphite hexamethylenetetramine which are capable to furnish formaldehyde for the reaction are also useful.

Where the term reacting agent or agent is used in the specification or claims, it is intended to mean either reactive aldehyde or materials such materials. Where the "activating" or "reacting" ingredients do not have inherent wetting properties, wetting agents may, if desired, be added to the solution or solutions being used.

In one mode of treatment, the hair is first impregnated with, for example, a I la-30% solution of the "activating agent for a period of time ranging from 5 to 60 minutes depending upon the reactivit of the hair, and the strength of the solution of the activating agent" etc. The period of time is variable and the period for most favorable results can easily be determined by simple experimenting with a few test strands of hair. The activated" hair is then brought into contact with the reacting" agent (i. e. formaldehyde or formaldehyde furnishing material). This agent is either poured or brushed on, or the hair may be steeped in the formaldehyde or formaldehyde producing substance in solution. Where a very dilute reacting solution is used, such as an 0.5% formaldehyde solution, several applications should be made, the effect thereof being cumulative.

According to another mode of treatment, a single solution containing, for example, 1% to 30% of the activating agent" and 3 to 30% of the reacting agent, together with suitable buflfer salts (where needed to establish the above prescribed pH range), and wetting agents if desirable, is used. After a waiting period from 5 to 50 minutes, during which the activating" and reacting" agents have an opportunity to penetrate into the hair, and react therewith, and with each other as explained more fully elsewhere herein. The temperature of the hair is raised by means of a heated comb, heating curlers, or the like. Where Negro hair is being straightened, an ordinary pressing comb" or pressing iron may be used. Where the straight hair of white humans is being curled, the hair is wrapped tightl around a mandrel and heated as is common practice in the hair waving art.

It is desirable to use as high a temperature as possible, temperatures from -200 0. being suitable.

To transmit the heat uniformly from the heating implement to the hair, I have found it advantageous to coat the hair with a heat conducting medium such as oils, petrolatum or the like, but preferably with triethanolamineoleate, or a similar compound resulting from the reaction between a substituted amine and fatty acids of a molecular weight sufllciently high so as to produce oily or waxy water-soluble or dispersabie products. Thus, after treatment of the hair with the activating" and reacting agents, triethanolamine-oleate may be worked into the hair and the hair then combed with a pressing comb (where straightening is desired) or wound on a mandrel (where curling is desired). The oily triethanolamine-oleate or other oily or greasy substance conducts the heat uniformly to the hair, when salts of amines and fatty acids are used as the heat conducting medium, and the activating 3 limitation on the technique herein illustrated, described and claimed.

More specifically, the molecules the hair, may be thought 0! as having the Structure 1.

Structure I 00 OH-CHMOHQOH/ Oystine linkage H agent" is of acidic nature, the excess acid is neutralized by the salt with the simultaneous liberation of the fatty acid originally combined with the amine, thus:

Cmuomsmnmmmonu ofinecoon Triethanolammonium Oleic acid crcsolsulfonate The effect of increased temperature is to permit the activating" and reacting" agents to complete their reactions upon the hair, producing condensation reactions in the hair and with the hair as well, as polymerizations of resinous or wax-like substances formed in situ.

It is my belief that the chemical mechanism by which the above described changes are produced in the hair of living beings can be rationalized as involving the breaking of the inner salt linkages in the molecular structure of the keratin of the hair and the formation of condensation products with the amino groups generated by the breaking o the inner salt Junctions.

This appears to be done without destroying the cystine linkages in the molecules upon which so many of the mechanical properties of the hair depend. This proposed explanation, more fully detailed below, is of course merely my theory of the process, and should not be considered as a In this structure, cystine linkages of the type shown exist along with inner salt linkages, some of which are composed of the glutamic acid-lysine nuclei, and others of the aspartic acid-arginine nuclei. The length of the molecular chain, the number and distributions of the cystine linkages and the number, kind and distributions of the inner salt linkages varies with difierent living beings and also varies with the diet of the individuals and possibly other environmental and hereditary factors. Indeed, the composition of the hair of any individual may vary from time to time as environmental conditions change, and the degree of reactivity of the hair of living beings in accordance with the present process varies with the individual, the race and condition, some being highly reactive and easily treated, others somewhat stubborn and resistant to change and reaction.

When the hair is subjected to the activating solutions having the prescribed pH in the range of 1 to 10, preferably 1-4.8 and 5.2 to 10, the inner salt linkages appear to be broken thus freeing the lysine nucleus and the arginine nucleus for reaction. The activating" agents heretofore defined may be represented by the general formula HX (where they are of the acidic type) or MOH (where they are of the basic type). The HX acid or MOH base adds onto the broken inner salt linkages as indicated in the formula (Str cture II).

Structure 1! oo co -on on- In this state, the hair molecules are rendered reactive. The amino groups (i. e. NH:) 0! the lysine and arginine groups, and apparently also, some of the imino groups (i. e. =NH) of the main portion of the molecule appear to be activated so as to be readily reacted upon by condensing or resinifying compounds in the reacting agents employed in this invention.

Thus the activated lysine group (see Structure II) may be thought of as reacting with formaldehyde in accordance with Equation I as follows:

Equation 1 Activated lysine nucleus H:C=N-CH:CH:CHI-CHl+H: H)

Iusoiubilized non-salt forming lysine nucleus The "activated lysine nucleus thus combined with the formaldehyde of the reacting" agent is rendered quite insoluble and relatively inert to further change.

Where the X portion of the activating reagent is capable of condensing with the reacting agent" to form resinous condensation products, this occurs, and resinous products are thus produced in situ in the hair thus further enhancing the permanent straightening 0r curling of the hair.- For example, when the activating" agent is sulfonic acid of a hydroxyaromatic or aminoarimatic compounds, the anion radical (represented by X in the above formulae) condenses with the "reacting agent e. g. formaldehyde to give Bakelite-like products which are formed in situ in the hair. Obviously, the X portion of the "activating agent may vary widely and it is desirably selected so as to be capabl of resinification.

This is likewise true of the M portion of the alkaline activating" agents, which may be selected for its ability to resinify with the "reacting agent. Thus, when morpholine having the 1 structure formula CHI-CH1 is used the hydroxyl attaches to the lysine or arginine nuclei and the remainder of the molecule (the radical herein represented as M) attaches Equation II (X or OH)E Formaldehyde I Argininc nucleus Structure III I hair dryer of the type generally used in beauty parlors. Then, a freshly made solution, preferably an aqueous solution, composed of 7%% cresol sulfonic acid, 7 /2% isopropyl naphthalene sulfonic acid, 10% pure formaldehyde, and water was applied generously to. the hair with a cotton swab so thatthe solution thoroughly impregnated the hair. The pH of this solution was 2-3 and therefore comes within the range of pH 1-4.8 previously specified. One application was made and the hair was thereafter allowed to stand minutes. The hair was then heated and combed with a "pressing comb." The comb was frequently heated over a gas flame to an esti- O O C 0\ -.-CH /CH /NH N H\ C O C O GH-CHa-S-S-CHz-CH Cystlne linkage \N 0 0 C O OH /CH /\NH 00 00 CH QH n r r ibl oo (PM so 00 CH- CHICHIC O 0-H or i H:C=N-CHrCHr-C Hr-CHr-CH Et/ Glutamic acid Insolubllized lysine N nucleus nucleus NH C O C O CH CH- \T g u C 0 C 0 CH-CHr-C O 0-H or M HzC=NC-NHCHr-C Hr-CHr-C Aspartic acid I N H H H Insolubilimd arginlne nucleus As more specific illustrations of the manner in which the invention may be carried out, reference may be made to the following examples which, however, are not to be considered as limitations upon the capabilities of the invention.

Example I In this example, the hair of a living Negress was treated and rendered straight instead of kinky. Before treatment, the hair was very kinky and bushy and averaged about 4 inches long from scalp to hair end. The hair was given a preliminary shampoo so as to remove oils and waxes previously used by this individual in the well known process of pressing" her hair. It may be mentioned parenthetically that the pressing" previously used by this individual was the usual method employed by Negroes and consisted of combing with a heavy metal heated comb while the hair is coated with petrolatunyor other waxy dressing. Such pressing does not produce permanent changes, since the temporarily straightened hair quickly reverts to the kinky condition upon being wetted.

After shampooing, the hair was dried with a mated temperature of 200 C. during the operation of combing with heat, and during combing. the hair was frequently dressed with triethanolammonium oleate applied by means of the fingers to the hair. The triethanolammonium oleate, being greasy, lubricated and greatly assisted in conducting the heat to the hair, and after completion of the combing operation, the hair was shampooed and dried, at which time the length of the hair had increased about 50% and th hair was straight, soft and silky. It is noteworthy that at this stage, the hairs were straight, even though wetted during the shampooing, and that the hair remained straight for months. By contrast, the same Negress had previously had to press her hair each week, the effect being only (Activating agent) Resorcinol mixtures:

Example II Per cent (Activating agent) Triethanolammonium resorcinol sulfonate (Reacting agent) Formaldehyde 10 The acidity of the solution may be adjusted to pH in the range of'pI-I 1-10 preferably in the range of 1-4.8 and 52-10 by the addition of resorcinol sulfonic acid or similar acids or by the addition of triethanolamine or similar hydroxyl producing substances.

Example III Per cent disulfonic acid 10 (Reacting agent) Hexamethylene tetramine. 10

This mixture is acidic and its hydrogen ion concentration is adjusted to give the desired pH by varying the ratios of the two solutions used. The hexamethylene tetramine operates by liberating formaldehyde as the reacting ingredient.

Example IV Per cent (Activating agent) Isopropyl naphthalene sulfonic acid 1% (Reacting agent) Hexamethylene tetramine. 10

This mixture is acidic and its hydrogen ion concentration is adjusted to give the desired pH by varying the ratios of the two solutions used. The hexamethylene tetramine operates by liberating formaldehyde as the reacting ingredient.

Example V Per cent (Activating agent) Triethanolamine 4 (Reacting agent) Formaldehyde 4 This mixture is alkaline having a pH of approximately 8.0.

Example VI Per cent (Activating agent) Aluminum sulfate 10 (Reacting agent) Formaldehyde 10 In this mixture the acidity was approximately pH 3.5.

Example VII Per cent (Activating agent):

Resorcinol sulfonic acid 7V Isopropyl naphthalene sulphonic acid 1% (Reacting agent):

Formaldehyde 10 The acidity of this mixture was approximately pH 1.

Example VIII Per cent (Activating agent) Aluminum cresol sulfonate 10 (Reacting agent) Formaldehyde The acidity of this mixture was approximately pH 1.5.

Example IX Per cent (Activating agent) Aluminum cresol sulfonate 10 (Reacting agent) Formaldehyde 20 The acidity of this mixture was approximately pH 1.5.

Example X Per cent (Activating agent) Triethanolamine 10 (Reacting agent) Formaldehyde 10 The alkalinity of this mixture was approximately pH 8.0.

Example XI Per cent (Activating agent) Triethanolamine 10 (Reacting agent) Hexamethylene tetramine. 10

The alkalinity of this mixture was approximately pH 8.5.

Example XII There also may be used as the reacting" agent a 20% solution of the addition product of 1 mol formaldehyde and 1 mol bisulflte to which, as the activating agent, there is added either 5-l5% triethanolamine (in which event the alkalinity is about pH 7.5-8.0), or 5-15% of one of the sulfonic acids aforementioned (in which event the mixture is acid in the range of pH 1-6.5).

It will be observed that in a l of the foregoing examples the pH conditions fall in the range of pH 1-10.

In all of the foregoing examples, III-XII, the hair of the subject is first shampooed as in Example I, and dried, or otherwise cleaned, as a precaution to render it uniformly receptive to the reacting ingredients. Then the solution of the activating agent or agents, and reacting" agent or agents is swabbed or brushed on, the most facile method being strand by strand with a common toothbrush. The solutions are then permitted to soak and dry for a period of time which may be determined, as stated before, by experimenting upon the subject. Usually from 5 to 60 minutes is required depending upon the reactivity of the hair. In the foregoing examples, where alkaline conditions are maintained an alkali-stable wetting agent such as the sodium salt of isopropyl naphthalene sulfonic acid may be used. In this material a concentration of 0.3% is desirable. When acid conditions are used any suitable acid stable wetting agent may be used.

After impregnation the hair is heated to a temperature of IOU-200 C. either with a heated comb or with heated curlers depending upon whether the hair is being straightened or curled, during which the hair is lubricated with oils, such as petrolatum, but preferably with the triethanolamine esters of long chain fatty acids such as triethanolamine oleate.

After the heat treatment, the hair is then again shampooed, dried and coiflured according to the choice of the individual. (I

It may be stated, that as a general rule the curling of the hair of whites is usually best accomplished by utilizing activating and reacting agents of the basictype, whereas the straightening of Negroes hair is best accomplished with such of the above solutions as are acidic in character, although individual variations from this general rule frequently occur.

When the alkaline earths and iron group salts of the acids are used asthe activating agents, the combing or curling with heat, in the presence of triethanolammonium oleate. or other similar fatty acid esters produces (in addition to the condensation and resinification reactions which depend upon the nature of the keratin and of the activating acid radical) a wax-like product which is formed in situ by the metathesis of the ester and the salt, the wax-like product being waterrepellant, lends this attribute to the finished hair.

By the term "reactive aldehyde nucleus as used in the claims, I mean an aldehyde nucleus which is capable of reacting with the keratin of the hair, or capable of forming resinous or condensation products.

The present application is a continuation-in- 1-10, and then heating the hair to effect the desired condensation reaction while maintaining the hair in the desired physical configuration.

6. The process of establishing a desired configuration in growing hair on living beings which comprises wetting the hair with an aqueous solution containing 3% to 30% of a compound of the class consisting of formaldehyde and formal; dehyde yielding substances; 1 /2% to 30% of an ionizable catalyst capable of establishing a sewlected pH in the range of 1 to 10, which ionizable tion containing to ,of a compound selected from the roup consisting of formaldehyde and formaldehyde yielding substances; and 1 /2% to 30% of an ionizable substance acting as a catalyst and establishing the pH of the solution in the range of 1 to 10, and then heating the hair to a temperature in the range of about 100, C. to 200 C. while maintaining the hair in the desired configuration.

2. The process of establishing a desired con.-

figuration in growing hair on living beings which comprises wetting the hair with an aqueous solution containing 3% to 30% of a compound selected from the class consisting of formaldehyde 200 C. while maintaining the hair in the desired physical configuration.

3. The process of establishing a desired con- I figuration in growing hair on living being which comprises wetting the hair with an aqueous solution containing 3% to 30% of a compound selected from the class consisting of formaldehyde and formaldehyde yielding substances; 1%% to 30% of an ionizable catalyst for establishing and maintaining the pH of the solution in the range of 5.2 tolO, and then heating the hair to a temperature in the range of about 100 C. to 200 C. while maintaining the hair in the desired physical configuration.

4. The process of establishing a desired configuration in growing hair on living beings which comprises wetting the hair with an aqueous solution containing 3% to 30% of a compound selected from the class consisting of formaldehyde and formaldehyde yielding substances; 1 /2% to 30% of an ionizable catalyst capable of establishing a selected pH in the range oil to 10, which ionizable catalyst is characterized by being capable of reacting with formaldehyde to form relatively water insoluble condensation products, and then heating the hair to a temperature in the range of 100 C. to 200 C. while maintaining the catalyst is characterized by being capable of reacting with formaldehyde to form relatively water insoluble condensation products and then heating the hair to effect the desired condensation reaction while maintaining the same in the physical configuration desired to be'produced.

7. The process of establishing a desired configuration in growing hair on living'beings which comprises wetting the hair with an aqueous solution containing 3% to 30% of a compound of the class consisting of formaldehyde and formaldehyde yielding substances; 1%% to 30% of an ionizable catalyst capable of establishing a selected pH in the range of 1 to 10, which ionizable catalyst is characterized by, being capable of reacting with formaldehyde to form relatively waterinsoluble condensation products, then heating the hair to effect the desired condensation reaction while maintaining the same in the physical configuration desired to be produced, and lubricating the hair while heating and combing.

8. The process of establishing a desired configuration in growing hair on living beings which comprises wetting the hair with an aqueous solution containing 3% to 30% of a compound of the class consisting of formaldehyde and formaldehyde yielding substances; 1%;% to 30% of an ionizable catalyst capable of establishing a selected pH in the range of 1 to 10, which ionizable catalyst is characterized by being capable of reacting with formaldehyde to form relatively water insoluble condensation products, then heating the hair to eifect the desired condensation reaction while maintainingthe same in the physical configuration desired to be produced, and lubricating the hair with an amine ester of a long chain fatty acid while the hair is heated and combed.

9. The process of establishing a desired configuration in growing hair on living beings which comprises wetting the hair with'an aqueous solution containing 3% to 30% of a compound of the class consisting of formaldehyde and formaldehyde yielding substances; 1 /2% to 30% of an ionizable catalyst capable of establishing a selected pH in the range of 1 to 10, which ionizable catalyst is characterized by being capable of reacting with formaldehyde to form relatively water insoluble condensation products and then heating the hair to efiect the desired condensation reaction while maintaining the same in the physical a long chain fatty acid while the hair is heated and combed.

10. The process of establishing a desired configuration in growing hair on living beings which comprises wetting the hair with an aqueous solution containing 3% to 30% of a compound of the class consisting of formaldehyde and formaldehyde yielding substances; 1 /2% to 30% of an ionizable catalyst capable of establishing a selected pH in the range of 1 to 10, which ionizable catalyst is characterized by being capable of reacting with formaldehyde to form relatively water insoluble condensation products, heating the hair to efiect the desired condensation reaction while maintaining the same in the physical configuration desired to be produced, the aqueous solution above specified and the ionizable catalyst being in a single solution.

11. The process of establishing a desired configuration in growing hair on a living being which comprises wetting the hair with an aqueous solution containing 3 to 30% o! a compound selected from the group consisting of an aldehyde capable of forming condensation products with the keratin of the hair, and substance yielding an aldehyde capable of forming condensation products with the keratin of the hair; and 1. /2 to 30% of an ionizable catalyst for establishing a pH in a selected range, which solution has a pH in the range of 1 to 10, and then heating the hair to effect the desired condensation reaction while maintaining the hair in the desired physical configuration.

JOSE B. CALVA. 

